/*
 * Copyright (C) 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.itranswarp.javapractice.plugin.repackaged.com.google.gson.internal.bind;

import java.io.IOException;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.net.InetAddress;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.Calendar;
import java.util.Currency;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicIntegerArray;

import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.Gson;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.JsonArray;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.JsonElement;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.JsonIOException;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.JsonNull;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.JsonObject;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.JsonPrimitive;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.JsonSyntaxException;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.TypeAdapter;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.TypeAdapterFactory;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.annotations.SerializedName;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.internal.LazilyParsedNumber;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.reflect.TypeToken;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.stream.JsonReader;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.stream.JsonToken;
import com.itranswarp.javapractice.plugin.repackaged.com.google.gson.stream.JsonWriter;

/**
 * Type adapters for basic types.
 */
public final class TypeAdapters {
	private TypeAdapters() {
		throw new UnsupportedOperationException();
	}

	@SuppressWarnings("rawtypes")
	public static final TypeAdapter<Class> CLASS = new TypeAdapter<Class>() {
		@Override
		public void write(JsonWriter out, Class value) throws IOException {
			if (value == null) {
				out.nullValue();
			} else {
				throw new UnsupportedOperationException("Attempted to serialize java.lang.Class: " + value.getName()
						+ ". Forgot to register a type adapter?");
			}
		}

		@Override
		public Class read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			} else {
				throw new UnsupportedOperationException(
						"Attempted to deserialize a java.lang.Class. Forgot to register a type adapter?");
			}
		}
	};
	public static final TypeAdapterFactory CLASS_FACTORY = newFactory(Class.class, CLASS);

	public static final TypeAdapter<BitSet> BIT_SET = new TypeAdapter<BitSet>() {
		@SuppressWarnings("incomplete-switch")
		@Override
		public BitSet read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}

			BitSet bitset = new BitSet();
			in.beginArray();
			int i = 0;
			JsonToken tokenType = in.peek();
			while (tokenType != JsonToken.END_ARRAY) {
				boolean set;
				switch (tokenType) {
				case NUMBER:
					set = in.nextInt() != 0;
					break;
				case BOOLEAN:
					set = in.nextBoolean();
					break;
				case STRING:
					String stringValue = in.nextString();
					try {
						set = Integer.parseInt(stringValue) != 0;
					} catch (NumberFormatException e) {
						throw new JsonSyntaxException(
								"Error: Expecting: bitset number value (1, 0), Found: " + stringValue);
					}
					break;
				default:
					throw new JsonSyntaxException("Invalid bitset value type: " + tokenType);
				}
				if (set) {
					bitset.set(i);
				}
				++i;
				tokenType = in.peek();
			}
			in.endArray();
			return bitset;
		}

		@Override
		public void write(JsonWriter out, BitSet src) throws IOException {
			if (src == null) {
				out.nullValue();
				return;
			}

			out.beginArray();
			for (int i = 0; i < src.length(); i++) {
				int value = (src.get(i)) ? 1 : 0;
				out.value(value);
			}
			out.endArray();
		}
	};

	public static final TypeAdapterFactory BIT_SET_FACTORY = newFactory(BitSet.class, BIT_SET);

	public static final TypeAdapter<Boolean> BOOLEAN = new TypeAdapter<Boolean>() {
		@Override
		public Boolean read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			} else if (in.peek() == JsonToken.STRING) {
				// support strings for compatibility with GSON 1.7
				return Boolean.parseBoolean(in.nextString());
			}
			return in.nextBoolean();
		}

		@Override
		public void write(JsonWriter out, Boolean value) throws IOException {
			if (value == null) {
				out.nullValue();
				return;
			}
			out.value(value);
		}
	};

	/**
	 * Writes a boolean as a string. Useful for map keys, where booleans aren't
	 * otherwise permitted.
	 */
	public static final TypeAdapter<Boolean> BOOLEAN_AS_STRING = new TypeAdapter<Boolean>() {
		@Override
		public Boolean read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			return Boolean.valueOf(in.nextString());
		}

		@Override
		public void write(JsonWriter out, Boolean value) throws IOException {
			out.value(value == null ? "null" : value.toString());
		}
	};

	public static final TypeAdapterFactory BOOLEAN_FACTORY = newFactory(boolean.class, Boolean.class, BOOLEAN);

	public static final TypeAdapter<Number> BYTE = new TypeAdapter<Number>() {
		@Override
		public Number read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			try {
				int intValue = in.nextInt();
				return (byte) intValue;
			} catch (NumberFormatException e) {
				throw new JsonSyntaxException(e);
			}
		}

		@Override
		public void write(JsonWriter out, Number value) throws IOException {
			out.value(value);
		}
	};

	public static final TypeAdapterFactory BYTE_FACTORY = newFactory(byte.class, Byte.class, BYTE);

	public static final TypeAdapter<Number> SHORT = new TypeAdapter<Number>() {
		@Override
		public Number read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			try {
				return (short) in.nextInt();
			} catch (NumberFormatException e) {
				throw new JsonSyntaxException(e);
			}
		}

		@Override
		public void write(JsonWriter out, Number value) throws IOException {
			out.value(value);
		}
	};

	public static final TypeAdapterFactory SHORT_FACTORY = newFactory(short.class, Short.class, SHORT);

	public static final TypeAdapter<Number> INTEGER = new TypeAdapter<Number>() {
		@Override
		public Number read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			try {
				return in.nextInt();
			} catch (NumberFormatException e) {
				throw new JsonSyntaxException(e);
			}
		}

		@Override
		public void write(JsonWriter out, Number value) throws IOException {
			out.value(value);
		}
	};
	public static final TypeAdapterFactory INTEGER_FACTORY = newFactory(int.class, Integer.class, INTEGER);

	public static final TypeAdapter<AtomicInteger> ATOMIC_INTEGER = new TypeAdapter<AtomicInteger>() {
		@Override
		public AtomicInteger read(JsonReader in) throws IOException {
			try {
				return new AtomicInteger(in.nextInt());
			} catch (NumberFormatException e) {
				throw new JsonSyntaxException(e);
			}
		}

		@Override
		public void write(JsonWriter out, AtomicInteger value) throws IOException {
			out.value(value.get());
		}
	}.nullSafe();
	public static final TypeAdapterFactory ATOMIC_INTEGER_FACTORY = newFactory(AtomicInteger.class,
			TypeAdapters.ATOMIC_INTEGER);

	public static final TypeAdapter<AtomicBoolean> ATOMIC_BOOLEAN = new TypeAdapter<AtomicBoolean>() {
		@Override
		public AtomicBoolean read(JsonReader in) throws IOException {
			return new AtomicBoolean(in.nextBoolean());
		}

		@Override
		public void write(JsonWriter out, AtomicBoolean value) throws IOException {
			out.value(value.get());
		}
	}.nullSafe();
	public static final TypeAdapterFactory ATOMIC_BOOLEAN_FACTORY = newFactory(AtomicBoolean.class,
			TypeAdapters.ATOMIC_BOOLEAN);

	public static final TypeAdapter<AtomicIntegerArray> ATOMIC_INTEGER_ARRAY = new TypeAdapter<AtomicIntegerArray>() {
		@Override
		public AtomicIntegerArray read(JsonReader in) throws IOException {
			List<Integer> list = new ArrayList<>();
			in.beginArray();
			while (in.hasNext()) {
				try {
					int integer = in.nextInt();
					list.add(integer);
				} catch (NumberFormatException e) {
					throw new JsonSyntaxException(e);
				}
			}
			in.endArray();
			int length = list.size();
			AtomicIntegerArray array = new AtomicIntegerArray(length);
			for (int i = 0; i < length; ++i) {
				array.set(i, list.get(i));
			}
			return array;
		}

		@Override
		public void write(JsonWriter out, AtomicIntegerArray value) throws IOException {
			out.beginArray();
			for (int i = 0, length = value.length(); i < length; i++) {
				out.value(value.get(i));
			}
			out.endArray();
		}
	}.nullSafe();
	public static final TypeAdapterFactory ATOMIC_INTEGER_ARRAY_FACTORY = newFactory(AtomicIntegerArray.class,
			TypeAdapters.ATOMIC_INTEGER_ARRAY);

	public static final TypeAdapter<Number> LONG = new TypeAdapter<Number>() {
		@Override
		public Number read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			try {
				return in.nextLong();
			} catch (NumberFormatException e) {
				throw new JsonSyntaxException(e);
			}
		}

		@Override
		public void write(JsonWriter out, Number value) throws IOException {
			out.value(value);
		}
	};

	public static final TypeAdapter<Number> FLOAT = new TypeAdapter<Number>() {
		@Override
		public Number read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			return (float) in.nextDouble();
		}

		@Override
		public void write(JsonWriter out, Number value) throws IOException {
			out.value(value);
		}
	};

	public static final TypeAdapter<Number> DOUBLE = new TypeAdapter<Number>() {
		@Override
		public Number read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			return in.nextDouble();
		}

		@Override
		public void write(JsonWriter out, Number value) throws IOException {
			out.value(value);
		}
	};

	public static final TypeAdapter<Number> NUMBER = new TypeAdapter<Number>() {
		@SuppressWarnings("incomplete-switch")
		@Override
		public Number read(JsonReader in) throws IOException {
			JsonToken jsonToken = in.peek();
			switch (jsonToken) {
			case NULL:
				in.nextNull();
				return null;
			case NUMBER:
				return new LazilyParsedNumber(in.nextString());
			default:
				throw new JsonSyntaxException("Expecting number, got: " + jsonToken);
			}
		}

		@Override
		public void write(JsonWriter out, Number value) throws IOException {
			out.value(value);
		}
	};

	public static final TypeAdapterFactory NUMBER_FACTORY = newFactory(Number.class, NUMBER);

	public static final TypeAdapter<Character> CHARACTER = new TypeAdapter<Character>() {
		@Override
		public Character read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			String str = in.nextString();
			if (str.length() != 1) {
				throw new JsonSyntaxException("Expecting character, got: " + str);
			}
			return str.charAt(0);
		}

		@Override
		public void write(JsonWriter out, Character value) throws IOException {
			out.value(value == null ? null : String.valueOf(value));
		}
	};

	public static final TypeAdapterFactory CHARACTER_FACTORY = newFactory(char.class, Character.class, CHARACTER);

	public static final TypeAdapter<String> STRING = new TypeAdapter<String>() {
		@Override
		public String read(JsonReader in) throws IOException {
			JsonToken peek = in.peek();
			if (peek == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			/* coerce booleans to strings for backwards compatibility */
			if (peek == JsonToken.BOOLEAN) {
				return Boolean.toString(in.nextBoolean());
			}
			return in.nextString();
		}

		@Override
		public void write(JsonWriter out, String value) throws IOException {
			out.value(value);
		}
	};

	public static final TypeAdapter<BigDecimal> BIG_DECIMAL = new TypeAdapter<BigDecimal>() {
		@Override
		public BigDecimal read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			try {
				return new BigDecimal(in.nextString());
			} catch (NumberFormatException e) {
				throw new JsonSyntaxException(e);
			}
		}

		@Override
		public void write(JsonWriter out, BigDecimal value) throws IOException {
			out.value(value);
		}
	};

	public static final TypeAdapter<BigInteger> BIG_INTEGER = new TypeAdapter<BigInteger>() {
		@Override
		public BigInteger read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			try {
				return new BigInteger(in.nextString());
			} catch (NumberFormatException e) {
				throw new JsonSyntaxException(e);
			}
		}

		@Override
		public void write(JsonWriter out, BigInteger value) throws IOException {
			out.value(value);
		}
	};

	public static final TypeAdapterFactory STRING_FACTORY = newFactory(String.class, STRING);

	public static final TypeAdapter<StringBuilder> STRING_BUILDER = new TypeAdapter<StringBuilder>() {
		@Override
		public StringBuilder read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			return new StringBuilder(in.nextString());
		}

		@Override
		public void write(JsonWriter out, StringBuilder value) throws IOException {
			out.value(value == null ? null : value.toString());
		}
	};

	public static final TypeAdapterFactory STRING_BUILDER_FACTORY = newFactory(StringBuilder.class, STRING_BUILDER);

	public static final TypeAdapter<StringBuffer> STRING_BUFFER = new TypeAdapter<StringBuffer>() {
		@Override
		public StringBuffer read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			return new StringBuffer(in.nextString());
		}

		@Override
		public void write(JsonWriter out, StringBuffer value) throws IOException {
			out.value(value == null ? null : value.toString());
		}
	};

	public static final TypeAdapterFactory STRING_BUFFER_FACTORY = newFactory(StringBuffer.class, STRING_BUFFER);

	public static final TypeAdapter<URL> URL = new TypeAdapter<URL>() {
		@Override
		public URL read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			String nextString = in.nextString();
			return "null".equals(nextString) ? null : new URL(nextString);
		}

		@Override
		public void write(JsonWriter out, URL value) throws IOException {
			out.value(value == null ? null : value.toExternalForm());
		}
	};

	public static final TypeAdapterFactory URL_FACTORY = newFactory(URL.class, URL);

	public static final TypeAdapter<URI> URI = new TypeAdapter<URI>() {
		@Override
		public URI read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			try {
				String nextString = in.nextString();
				return "null".equals(nextString) ? null : new URI(nextString);
			} catch (URISyntaxException e) {
				throw new JsonIOException(e);
			}
		}

		@Override
		public void write(JsonWriter out, URI value) throws IOException {
			out.value(value == null ? null : value.toASCIIString());
		}
	};

	public static final TypeAdapterFactory URI_FACTORY = newFactory(URI.class, URI);

	public static final TypeAdapter<InetAddress> INET_ADDRESS = new TypeAdapter<InetAddress>() {
		@Override
		public InetAddress read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			// regrettably, this should have included both the host name and the host
			// address
			return InetAddress.getByName(in.nextString());
		}

		@Override
		public void write(JsonWriter out, InetAddress value) throws IOException {
			out.value(value == null ? null : value.getHostAddress());
		}
	};

	public static final TypeAdapterFactory INET_ADDRESS_FACTORY = newTypeHierarchyFactory(InetAddress.class,
			INET_ADDRESS);

	public static final TypeAdapter<UUID> UUID = new TypeAdapter<UUID>() {
		@Override
		public UUID read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			return java.util.UUID.fromString(in.nextString());
		}

		@Override
		public void write(JsonWriter out, UUID value) throws IOException {
			out.value(value == null ? null : value.toString());
		}
	};

	public static final TypeAdapterFactory UUID_FACTORY = newFactory(UUID.class, UUID);

	public static final TypeAdapter<Currency> CURRENCY = new TypeAdapter<Currency>() {
		@Override
		public Currency read(JsonReader in) throws IOException {
			return Currency.getInstance(in.nextString());
		}

		@Override
		public void write(JsonWriter out, Currency value) throws IOException {
			out.value(value.getCurrencyCode());
		}
	}.nullSafe();
	public static final TypeAdapterFactory CURRENCY_FACTORY = newFactory(Currency.class, CURRENCY);

	public static final TypeAdapterFactory TIMESTAMP_FACTORY = new TypeAdapterFactory() {
		@SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
		@Override
		public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
			if (typeToken.getRawType() != Timestamp.class) {
				return null;
			}

			final TypeAdapter<Date> dateTypeAdapter = gson.getAdapter(Date.class);
			return (TypeAdapter<T>) new TypeAdapter<Timestamp>() {
				@Override
				public Timestamp read(JsonReader in) throws IOException {
					Date date = dateTypeAdapter.read(in);
					return date != null ? new Timestamp(date.getTime()) : null;
				}

				@Override
				public void write(JsonWriter out, Timestamp value) throws IOException {
					dateTypeAdapter.write(out, value);
				}
			};
		}
	};

	public static final TypeAdapter<Calendar> CALENDAR = new TypeAdapter<Calendar>() {
		private static final String YEAR = "year";
		private static final String MONTH = "month";
		private static final String DAY_OF_MONTH = "dayOfMonth";
		private static final String HOUR_OF_DAY = "hourOfDay";
		private static final String MINUTE = "minute";
		private static final String SECOND = "second";

		@Override
		public Calendar read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			in.beginObject();
			int year = 0;
			int month = 0;
			int dayOfMonth = 0;
			int hourOfDay = 0;
			int minute = 0;
			int second = 0;
			while (in.peek() != JsonToken.END_OBJECT) {
				String name = in.nextName();
				int value = in.nextInt();
				if (YEAR.equals(name)) {
					year = value;
				} else if (MONTH.equals(name)) {
					month = value;
				} else if (DAY_OF_MONTH.equals(name)) {
					dayOfMonth = value;
				} else if (HOUR_OF_DAY.equals(name)) {
					hourOfDay = value;
				} else if (MINUTE.equals(name)) {
					minute = value;
				} else if (SECOND.equals(name)) {
					second = value;
				}
			}
			in.endObject();
			return new GregorianCalendar(year, month, dayOfMonth, hourOfDay, minute, second);
		}

		@Override
		public void write(JsonWriter out, Calendar value) throws IOException {
			if (value == null) {
				out.nullValue();
				return;
			}
			out.beginObject();
			out.name(YEAR);
			out.value(value.get(Calendar.YEAR));
			out.name(MONTH);
			out.value(value.get(Calendar.MONTH));
			out.name(DAY_OF_MONTH);
			out.value(value.get(Calendar.DAY_OF_MONTH));
			out.name(HOUR_OF_DAY);
			out.value(value.get(Calendar.HOUR_OF_DAY));
			out.name(MINUTE);
			out.value(value.get(Calendar.MINUTE));
			out.name(SECOND);
			out.value(value.get(Calendar.SECOND));
			out.endObject();
		}
	};

	public static final TypeAdapterFactory CALENDAR_FACTORY = newFactoryForMultipleTypes(Calendar.class,
			GregorianCalendar.class, CALENDAR);

	public static final TypeAdapter<Locale> LOCALE = new TypeAdapter<Locale>() {
		@Override
		public Locale read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			String locale = in.nextString();
			StringTokenizer tokenizer = new StringTokenizer(locale, "_");
			String language = null;
			String country = null;
			String variant = null;
			if (tokenizer.hasMoreElements()) {
				language = tokenizer.nextToken();
			}
			if (tokenizer.hasMoreElements()) {
				country = tokenizer.nextToken();
			}
			if (tokenizer.hasMoreElements()) {
				variant = tokenizer.nextToken();
			}
			if (country == null && variant == null) {
				return new Locale(language);
			} else if (variant == null) {
				return new Locale(language, country);
			} else {
				return new Locale(language, country, variant);
			}
		}

		@Override
		public void write(JsonWriter out, Locale value) throws IOException {
			out.value(value == null ? null : value.toString());
		}
	};

	public static final TypeAdapterFactory LOCALE_FACTORY = newFactory(Locale.class, LOCALE);

	public static final TypeAdapter<JsonElement> JSON_ELEMENT = new TypeAdapter<JsonElement>() {
		@Override
		public JsonElement read(JsonReader in) throws IOException {
			switch (in.peek()) {
			case STRING:
				return new JsonPrimitive(in.nextString());
			case NUMBER:
				String number = in.nextString();
				return new JsonPrimitive(new LazilyParsedNumber(number));
			case BOOLEAN:
				return new JsonPrimitive(in.nextBoolean());
			case NULL:
				in.nextNull();
				return JsonNull.INSTANCE;
			case BEGIN_ARRAY:
				JsonArray array = new JsonArray();
				in.beginArray();
				while (in.hasNext()) {
					array.add(read(in));
				}
				in.endArray();
				return array;
			case BEGIN_OBJECT:
				JsonObject object = new JsonObject();
				in.beginObject();
				while (in.hasNext()) {
					object.add(in.nextName(), read(in));
				}
				in.endObject();
				return object;
			case END_DOCUMENT:
			case NAME:
			case END_OBJECT:
			case END_ARRAY:
			default:
				throw new IllegalArgumentException();
			}
		}

		@Override
		public void write(JsonWriter out, JsonElement value) throws IOException {
			if (value == null || value.isJsonNull()) {
				out.nullValue();
			} else if (value.isJsonPrimitive()) {
				JsonPrimitive primitive = value.getAsJsonPrimitive();
				if (primitive.isNumber()) {
					out.value(primitive.getAsNumber());
				} else if (primitive.isBoolean()) {
					out.value(primitive.getAsBoolean());
				} else {
					out.value(primitive.getAsString());
				}

			} else if (value.isJsonArray()) {
				out.beginArray();
				for (JsonElement e : value.getAsJsonArray()) {
					write(out, e);
				}
				out.endArray();

			} else if (value.isJsonObject()) {
				out.beginObject();
				for (Map.Entry<String, JsonElement> e : value.getAsJsonObject().entrySet()) {
					out.name(e.getKey());
					write(out, e.getValue());
				}
				out.endObject();

			} else {
				throw new IllegalArgumentException("Couldn't write " + value.getClass());
			}
		}
	};

	public static final TypeAdapterFactory JSON_ELEMENT_FACTORY = newTypeHierarchyFactory(JsonElement.class,
			JSON_ELEMENT);

	private static final class EnumTypeAdapter<T extends Enum<T>> extends TypeAdapter<T> {
		private final Map<String, T> nameToConstant = new HashMap<>();
		private final Map<T, String> constantToName = new HashMap<>();

		public EnumTypeAdapter(Class<T> classOfT) {
			try {
				for (T constant : classOfT.getEnumConstants()) {
					String name = constant.name();
					SerializedName annotation = classOfT.getField(name).getAnnotation(SerializedName.class);
					if (annotation != null) {
						name = annotation.value();
						for (String alternate : annotation.alternate()) {
							nameToConstant.put(alternate, constant);
						}
					}
					nameToConstant.put(name, constant);
					constantToName.put(constant, name);
				}
			} catch (NoSuchFieldException e) {
				throw new AssertionError("Missing field in " + classOfT.getName(), e);
			}
		}

		@Override
		public T read(JsonReader in) throws IOException {
			if (in.peek() == JsonToken.NULL) {
				in.nextNull();
				return null;
			}
			return nameToConstant.get(in.nextString());
		}

		@Override
		public void write(JsonWriter out, T value) throws IOException {
			out.value(value == null ? null : constantToName.get(value));
		}
	}

	public static final TypeAdapterFactory ENUM_FACTORY = new TypeAdapterFactory() {
		@SuppressWarnings({ "rawtypes", "unchecked" })
		@Override
		public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
			Class<? super T> rawType = typeToken.getRawType();
			if (!Enum.class.isAssignableFrom(rawType) || rawType == Enum.class) {
				return null;
			}
			if (!rawType.isEnum()) {
				rawType = rawType.getSuperclass(); // handle anonymous subclasses
			}
			return (TypeAdapter<T>) new EnumTypeAdapter(rawType);
		}
	};

	public static <TT> TypeAdapterFactory newFactory(final TypeToken<TT> type, final TypeAdapter<TT> typeAdapter) {
		return new TypeAdapterFactory() {
			@SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
			@Override
			public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
				return typeToken.equals(type) ? (TypeAdapter<T>) typeAdapter : null;
			}
		};
	}

	public static <TT> TypeAdapterFactory newFactory(final Class<TT> type, final TypeAdapter<TT> typeAdapter) {
		return new TypeAdapterFactory() {
			@SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
			@Override
			public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
				return typeToken.getRawType() == type ? (TypeAdapter<T>) typeAdapter : null;
			}

			@Override
			public String toString() {
				return "Factory[type=" + type.getName() + ",adapter=" + typeAdapter + "]";
			}
		};
	}

	public static <TT> TypeAdapterFactory newFactory(final Class<TT> unboxed, final Class<TT> boxed,
			final TypeAdapter<? super TT> typeAdapter) {
		return new TypeAdapterFactory() {
			@SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
			@Override
			public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
				Class<? super T> rawType = typeToken.getRawType();
				return (rawType == unboxed || rawType == boxed) ? (TypeAdapter<T>) typeAdapter : null;
			}

			@Override
			public String toString() {
				return "Factory[type=" + boxed.getName() + "+" + unboxed.getName() + ",adapter=" + typeAdapter + "]";
			}
		};
	}

	public static <TT> TypeAdapterFactory newFactoryForMultipleTypes(final Class<TT> base,
			final Class<? extends TT> sub, final TypeAdapter<? super TT> typeAdapter) {
		return new TypeAdapterFactory() {
			@SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
			@Override
			public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
				Class<? super T> rawType = typeToken.getRawType();
				return (rawType == base || rawType == sub) ? (TypeAdapter<T>) typeAdapter : null;
			}

			@Override
			public String toString() {
				return "Factory[type=" + base.getName() + "+" + sub.getName() + ",adapter=" + typeAdapter + "]";
			}
		};
	}

	/**
	 * Returns a factory for all subtypes of {@code typeAdapter}. We do a runtime
	 * check to confirm that the deserialized type matches the type requested.
	 */
	public static <T1> TypeAdapterFactory newTypeHierarchyFactory(final Class<T1> clazz,
			final TypeAdapter<T1> typeAdapter) {
		return new TypeAdapterFactory() {
			@SuppressWarnings("unchecked")
			@Override
			public <T2> TypeAdapter<T2> create(Gson gson, TypeToken<T2> typeToken) {
				final Class<? super T2> requestedType = typeToken.getRawType();
				if (!clazz.isAssignableFrom(requestedType)) {
					return null;
				}
				return (TypeAdapter<T2>) new TypeAdapter<T1>() {
					@Override
					public void write(JsonWriter out, T1 value) throws IOException {
						typeAdapter.write(out, value);
					}

					@Override
					public T1 read(JsonReader in) throws IOException {
						T1 result = typeAdapter.read(in);
						if (result != null && !requestedType.isInstance(result)) {
							throw new JsonSyntaxException("Expected a " + requestedType.getName() + " but was "
									+ result.getClass().getName());
						}
						return result;
					}
				};
			}

			@Override
			public String toString() {
				return "Factory[typeHierarchy=" + clazz.getName() + ",adapter=" + typeAdapter + "]";
			}
		};
	}
}
